Keystrokes entered by a user at a keyboard or other user input device may be monitored by software on the host computer. Alternatively, a device may be connected between the keyboard and the host computer, as described in the co-pending application published as WO 04/097614. Commercially available hardware keystroke monitoring devices and software record keystrokes into a log that can be retrieved later by users.
Newer models include time stamping features that record the time and date at regular intervals after the device is activated. This is generally a useful feature. However, when there are significant intervals between keystrokes it may be difficult to determine exactly when the keys of interest were typed. It is currently not easy to differentiate sessions of typing when they are interspersed with large time intervals. Also, the time stamp is simply entered at periodic intervals and is therefore placed arbitrarily in the keystroke log. A time stamp may be placed between letters and be difficult to find.
Where time stamping capability is added to a hardware device, a larger battery is required to power the internal clock. This means that the device is larger and more conspicuous, unless the keystroke monitor is embedded into the keyboard. However, some devices plug directly into the keyboard port of the computer and the larger size is undesirable for such devices.
In prior software methods and hardware devices it is also possible to tamper with the recorded log and/or internal clock of the device. This means that the evidence recorded by the monitor is unreliable for law enforcement purposes.
There is a need for an apparatus and method that alleviates these problems in the prior art.
It is an object of the invention to allow keystrokes and time stamps to be recorded in such a manner that the resulting log can be more easily interpreted by users.
It is a further object of the invention to provide a hardware device in which keystrokes and time stamps are recorded in such a manner that the resulting log can be more easily interpreted by users.
It is a further object of the invention to improve reliability of the keystroke log.
It is a further object of the invention to provide a hardware keystroke monitoring device with time stamping capability which is less conspicuous than prior devices.
Each object is to be read disjunctively with the object of at least providing the public with a useful choice.